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JSP Bean的开发



 



DB类 主要用于连接数据库以及数据库的关闭



package com.trendcom.db;



 



import java.sql.Connection;



import java.sql.DriverManager;



import java.sql.ResultSet;



import java.sql.Statement;



 



public class DbBase {



       



       public static Connection getConnection() throws Exception {



              String connUrl = \"jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=companyDb\";



              String dbDrv = \"com.microsoft.jdbc.sqlserver.SQLServerDriver\";



              String dbLogin = \"sa\";



              String dbPw = \"sa\";



              Connection con = null;



              try {



                     Class.forName(dbDrv).newInstance();



                     con = DriverManager.getConnection(connUrl, dbLogin, dbPw);



              } catch (Exception e) {



                     e.printStackTrace();



              }



              return con;



       }



       



       /**



        * 关闭一个Connection，关闭时对是否为null进行判断



        * 



        * @param con



        *            要关闭的Connection



        */



       public static void closeConnection(Connection con) {



              try {



                     if (con != null && !con.isClosed())



                            con.close();



              } catch (Exception e) {



                     e.printStackTrace();



              }



       }



 



       /**



        * 关闭一个ResultSet，关闭时对是否为null进行判断



        * 



        * @param rs



        *            要关闭的ResultSet



        */



       public static void closeResultSet(ResultSet rs) {



              try {



                     if (rs != null)



                            rs.close();



              } catch (Exception e) {



                     e.printStackTrace();



              }



       }



 



       /**



        * 关闭一个Statement，关闭时对是否为null进行判断



        * 



        * @param stmt



        *            要关闭的Statement



        */



       public static void closeStatement(Statement st) {



              try {



                     if (st != null)



                            st.close();



              } catch (Exception e) {



                     e.printStackTrace();



              }



       }



}



 



DBUtil 主要执行SQL返回List List中的对像使用Map相对应



 



package com.trendcom.db;



 



import java.sql.*;



import java.util.ArrayList;



import java.util.HashMap;



import java.util.List;



import java.util.Map;



 



 



public class DBUtil extends DbBase {



 



       @SuppressWarnings(\"unchecked\")



       public static List selectCommand(String sql) throws Exception {



              List list=new ArrayList();



              Connection conn = getConnection();



              Statement ps = null ;



              ResultSet rs = null;



              try{



              String[] colName=getColName(sql, conn);



               ps = conn.createStatement();



               rs = ps.executeQuery(sql);



              while(rs.next()){



                     Map map=new HashMap();



                     for(int i=1;i<colName.length;i  ){



                            if(rs.getMetaData().getColumnType(i)==Types.TIMESTAMP){



                                   map.put(colName,rs.getDate(i));



                            }else{



                                   map.put(colName,rs.getString(i));



                            }



                     }



                     list.add(map);



              }



              }catch(Exception ex){



                     ex.printStackTrace();



              }finally{



                     closeStatement(ps);



                     closeResultSet(rs);



                     closeConnection(conn);



              }



              return list;



       }



       



       



       public static String getSingleStringColumn(String sql) throws Exception {



              Connection conn = getConnection();



              String result=\"\";



              Statement ps = null ;



              ResultSet rs = null;



              try {



                      ps = conn.createStatement();



                      rs = ps.executeQuery(sql);



                     if (rs.next()) {



                            result = rs.getString(1);



                     }



              } catch (Exception e) {



                     e.printStackTrace();



 



              } finally {



                     closeStatement(ps);



                     closeResultSet(rs);



                     closeConnection(conn);



              }



              return result;



       }



       



       public static String[] getColName(String sql,Connection connection) throws Exception{



              ResultSet rs;



              Connection conn = connection;



              Statement ps=conn.createStatement();



              rs=ps.executeQuery(sql);



              String[] colName=new String[rs.getMetaData().getColumnCount() 1];



              for (int i = 1; i <colName.length; i  ) {



                     colName